Study on the Performance of Copper-Manganese Composite Oxide Catalysts for Toluene

Copper-manganese (CuMn) composite oxide catalysts were prepared for the catalytic combustion of a common volatile organic compound, namely toluene. The structural properties of the catalysts were analysed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) theory, X-ray photoelectron spectroscopy (XPS) and hydrogen temperature-programmed reduction (H-2-TPR). The catalytic stability was examined after 100 h. It was found that Cu1Mn1 exhibited the highest catalytic ability when the molar ratio of Cu : Mn was 1 : 1. The removal of toluene reached 90 % at a temperature below 229 degrees C. It was speculated that the Cu1.5Mn1.5O4 spinel structure and CuO were formed in the catalyst. The catalyst surface area was not the main factor affecting the catalytic activity. The catalysts displayed good stability and maintained high catalytic activity for a long time. Notably, fresh catalysts contained high amounts of high-valent Mn4+ and Cu2+ cations, which played important roles in the catalytic combustion of toluene. The cations initiated the redox process and led to the conversion of toluene to CO2 and H2O. The reduced lattice oxygen supplied from air was transformed into surface oxygen on the catalyst. The catalytic combustion of toluene in the presence of CuMn composite oxide catalysts followed the Mars-van Krevelen mechanism.